Fluorovinyl ethers and polymers obtainable therefrom

ABSTRACT

Fluorovinyl ethers having the formula CFX═CXOCF 2 OR, wherein R is a C 2 -C 6  linear, branched or C 5 -C 6  cyclic (per)fluoroalkyl group, or a C 2 -C 6  linear, branched (per)fluoro oxyalkyl group containing from one to three oxygen atoms; when R is fluoroalkyl or fluorooxyalkyl group as above defined, it can contain from 1 to 2 atoms, equal or different, selected from the following: H, Cl, Br, I; X═F, H; and homopolymers or polymers obtainable polymerizing said Fluorovinyl ethers with at least another polymerizable monomer.

The present invention relates to Fluorovinyl ethers, the process forpreparing them and the polymers obtainable therefrom.

It is well known that perfluoroalkyl vinyl ethers are generally used asmonomers for the olefin copolymerization, specifically copolymerizationwith tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene(CTFE), and/or hexafluoropropene. The introduction of small-amounts ofperfluoroalkyl vinyl ethers in plastomeric polymers implies a higherpolymer processability and better hot mechanical properties. Theintroduction of high amounts of perfluorovinyl ethers in crosslinkablefluoropolymers implies elastomeric properties at low temperature offluorinated rubbers.

The need was felt, in the fluorinated polymeric material field, toproduce both plastomers having good properties at high temperatures, andelastomers having improved properties at low temperatures by using onlyone fluorovinyl ether.

Such properties at low temperatures can generally be expressed by theglass transition temperature Tg.

Furthermore the need was felt to have available amorphous or crystallinecopolymers having a low content of C(O)F end groups. A lower content ofC(O)F end groups leads to obtain polymers having a higher thermalstability. A lower Tg allows to have elastomeric polymers which can beused at lower temperatures and therefore to have available elastomerswith a wider use range. To obtain the combination of the above mentionedproperties, fluorovinyl ethers must have a high unitary capability tomodify the base backbone properties, as well as high reactivity to beused as comonomers both in plastomeric and in elastomericfluoropolymers. It was desirable to have available vinyl ethersobtainable by simple processes having a limited number of steps.Preferably it would be desirable to have available a continuous processfor preparing said vinyl ethers.

To solve the above identified technical problem, fluorovinyl ethershaving different structural properties, have been proposed in the priorart. However from the prior art, hereinafter described, various unsolvedproblems result evident in the perfluorovinyl ether synthesis and in thepreparation of the corresponding polymers having the combination of theabove mentioned properties.

Patent U.S. Pat. No. 3,132,123 describes the preparation ofperfluoroalkyl vinyl ethers, of the corresponding homopolymers andcopolymers with TFE. Homopolymers are obtained under extremeexperimental conditions, by using polymerization pressures from 4,000 to18,000 atm. The perfluoromethylvinylether (PMVE) homopolymer is anelastomer: the Tg is not reported.

The general formula of the described vinyl ethers is the following:CF₂═CFOR^(O) _(F)wherein R^(O) _(F) is a perfluoroalkyl radical preferably from 1 to 5carbon atoms. A process for preparing these vinyl ethers is described inPatent U.S. Pat. No. 3,291,843 wherein the starting acylfluoride issolidified and pyrolized with carbonates also in the presence ofsolvents. By this process undesired hydrogenated by products areobtained.

Patent U.S. Pat. No. 3,450,684 relates to vinyl ethers having theformula:CF₂═CFO (CF₂CFX⁰O)_(n), CF₂CF₂X⁰wherein X⁰═F, Cl, CF₃, H and n′ can range from 1 to 20. Alsohomopolymers obtained by UV polymerization are reported. The exemplifiedcopolymers are not characterized by their properties at lowtemperatures.

Patent U.S. Pat. No. 3,635,926 relates to the emulsion copolymerizationof perfluorovinyl ethers with TFE, showing that the presence of —C(O)Facylfluoride end groups makes the polymers unstable. The same phenomenonwas already reported in U.S. Pat. No. 3,085,083 in the perfluorovinylether polymerization systems in solvent.

Patent U.S. Pat. No. 3,817,960 relates to the preparation andpolymerization of perfluorovinyl ethers having the formulaCF₃O(CF₂O)_(n″)CF₂CF₂OCF═CF₂wherein n″ can range from 1 to 5. The compound synthesis is complex, itrequires three steps. The preparation of the starting compoundCF₃O(CF₂O)_(n″)CF₂C(O)F is carried out by oxidation at low temperaturein the presence of U.V. radiations; besides the condensation with HFPO(hexafluoropropenoxide) and the subsequent alkaline pyrolysis isnecessary. No data on the above indicated properties are reported. Withregard to this see Patent application U.S. Pat. No. 5,910,552.

Patent U.S. Pat. No. 3,896,179 relates to the separation of “primary”isomers of perfluorovinyl ethers, for example of CF₃CF₂CF₂OCF═CF₂ fromthe corresponding less stable “secondary” isomers CF₃(CF₃)CFOCF═CF₂. Thelatter are undesired products as regards both the polymer preparationand the poor properties of the obtained polymers.

Patent U.S. Pat. No. 4,340,750 relates to the preparation ofperfluorovinyl ethers having the formulaCF₂═CFOCF₂R^(o) _(f)X¹wherein R^(o) _(f) is a C₁-C₂₀ perfluoroalkyl optionally containingoxygen, X¹═H, Cl, Br, F, COOR^(O), CONR^(O)R′ wherein R^(o) is a C₁-C₁₀alkyl group and R′ represents H or a C₁-C₁₀ alkyl group. In thepreparation of these compounds an acylfluoride together with iodine andtetrafluoroethylene is used, avoiding the final step of the acylfluoridepyrolysis which comes from the perfluoro-propene epoxide, by adeiodofluorination reaction, which takes place with low yields.

Patent U.S. Pat. No. 4,487,903 relates to the preparation offluoroelastomeric copolymers (i.e., elastomeric fluoropolymers) usingperfluorovinyl ethers having the formula:CF₂═CF(OCF₂CFY^(O))_(n) ^(o)OX²wherein n⁰ ranges from 1 to 4; Y^(O)═F, Cl, CF₃, H; X² can be C₁-C₃perfluoroalkyl group, C₁-C₃ ω-hydroperfluoroalkyl group, C₁-C₃ω-chloroperfluoroalkyl group. The polymer has a content of fluorovinylether units ranging from 15 to 50% by moles. These vinyl ethers givecopolymers which at low temperatures have better properties than thoseof the above mentioned perfluorovinyl ethers PVE (perfluoropropyl vinylether) and MVE type. In the patent it is disclosed that in order to havegood properties at low temperature, the presence of at least two etherbonds in the side chain adjacent to the double bond is required.Furthermore from the patent it results that for values higher than 4 itis difficult to purify the monomers and the effect on the decrease ofthe polymer T_(g) is lower. Besides the reactivity of the describedvinyl ethers is very low and it is difficult to obtain polymers having ahigh molecular weight able to give good elastomeric properties. ATFE/perfluorovinyl ether copolymer (n^(o)=2) 73/27% by moles with Tg of−32° C. is exemplified. However the polymer is obtained with very longreaction times (96 hours of polymerization).

Patent EP 130,052 describes the perfluoro(vinyl polyether) (PVPE)polymerization which leads to amorphous perfluoropolymers with a T_(g)ranging from −15 to −100° C. The described polymers have T_(g) valuesreaching up to −76° C.; the further T_(g) decrease is obtained by usingperfluoropolyethers as plasticizers. In the patent copolymers andterpolymers of TFE and MVE with vinylethers (PVPE) having the formulaCF₂═CFO(CF₂CF(CF₃)0)_(n′″)R^(o) _(f),are described, wherein n′″ ranges from 3 to 30 and R^(o) _(f), is aperfluoroalkyl group. Due to purification difficulties, the used vinylethers are vinylether mixtures with different n′″ values. According tosaid patent the most evident effect on the T_(g) decrease is shown whenn′ is equal to or higher than 3, preferably higher than 4. According tothe polymerization examples described in said patent the final mass ofthe polymer, besides the hot and under vacuum treatment, must then bewashed with Freon® TF (chlorofluorocarbon) in order to remove all theunreacted monomer (PVPE). From the Examples it results that thereactivity of all the described monomers (PVPE) is poor.

U.S. Pat. No. 4,515,989 relates to the preparation of new intermediatesfor the fluorovinyl ether synthesis. According to the patent thevinylether synthesis is improved by using an intermediate able to moreeasily decarboxylate. For its preparation fluoroepoxides of formula:X³CF₂—CF—CF₂ wherein X³═Cl, Br

are used.

U.S. Pat. No. 4,619,983 describes the copolymerization of VDF with vinylethers having the formula:CF₂═CFOX⁴wherein X⁴ is a C₃-C₉ oxyperfluoroalkyl radical containing from 1 to 3oxygen atoms. The obtained polymers are not perfluorinated polymers andshow a poor stability to alcohols.

U.S. Pat. No. 4,766,190 relates to the polymerization ofperfluorovinylpolyethers (PVPE) similar to those of U.S. Pat. No.4,487,903 with TFE and low perfluoropropene percentages, in order toimprove the mechanical properties of the obtained polymers.

Patent EP 338,755 relates to the preparation of perfluorinatedcopolymers by using direct fluorination of partially fluorinatedcopolymers. More reactive partially fluorinated monomers are used,subjecting the obtained polymers are fluorinated with elementalfluorine. The fluorination step requires a supplementary process unit,besides in this step elemental fluorine is used, which is a highlyoxidizing gas, with the consequent precautions connected to its use.Besides in the patent it is stated that in order not to compromise thefluorination reaction and the properties of the obtained polymer, usingthe invention process the percentage of the comonomer in the polymercannot exceed 50% by moles.

U.S. Pat. No. 5,268,405 reports the preparation of perfluorinatedrubbers having a low Tg, by the use of high viscosityperfluoropolyethers as plasticizers of perfluorinated rubbers (TFE/MVEcopolymers). However during the use perfluoropolyether bleeds takeplace. This is true especially for the PFPE having a low molecularweight (low viscosity): in said patent, therefore, the high viscosityPFPE use is suggested, and therefore the low viscosity PFPEs mustpreviously be removed from these last.

U.S. Pat. No. 5,350,497 relates to the preparation of perfluoroalkylvinyl ethers by fluorination with elemental fluorine ofhydrofluorochloroethers and subsequent dechlorination.

U.S. Pat. No. 5,401,818 relates to the preparation of perfluorovinylethers of formula:R¹ _(f)(OCF₂CF₂CF₂)_(m), —OCF═CF₂(wherein R¹ _(f) is a C₁-C₃ perfluoroalkyl radical and m, is an integerranging from 1 to 4) and of the corresponding copolymers having improvedproperties at low temperature. The preparation of said perfluorovinylethers is carried out by 7 steps, some of them have very low yields, andcomprise also a fluorination with elemental F₂. The reactivity of saidperfluorovinyl ethers is anyhow low.

As it is shown from the above prior art, the perfluorovinyl ethersynthesis generally involves a multistep process with low yields (U.S.Pat. Nos. 3,132,123 and 3,450,684), with additional purifications toremove undesired isomers (U.S. Pat. No. 3,896,179) and the need tocontrol the undesired hydrogenated by-products (U.S. Pat. No.3,291,843). Alternatively, in the synthesis substances acting asintermediates, which are suitably prepared, and which allow to eliminatesaid drawbacks (U.S. Pat. Nos. 4,340,750 and 4,515,989), are used.

Furthermore in some cases the vinylether preparation requires thefluorination with elemental fluorine of partially fluorinatedintermediates (U.S. Pat. No. 5,350,497); or, to avoid synthesis and lowreactivity problems of the perfluorovinyl ethers, fluorination ofpartially fluorinated polymers (EP 338,755) is suggested.

Other problems shown in the prior art relate to the low reactivity ofthe perfluorovinyl ethers, which makes it necessary the recovery of theunreacted monomers from the reaction raw products (English Patent UK1,514,700), and the stability problems for the polymers having —C(O)Fend groups (U.S. Pat. No. 3,635,926). These unstable end groups can betransformed by suitable reactants in order to increase the stability ofthe fluorinated polymer (EP 178,935).

Perfluoro(oxyalkyl vinyl ethers) are used to confer to the fluorinatedrubbers good properties at low temperatures, and specifically to lowerthe copolymer glass transition temperature.

By increasing the perfluorooxyalkyl units forming the sideperfluorooxyalkyl substituent, the T_(g) of the corresponding obtainableamorphous copolymers decreases, but at the same time the reactivity ofthe vinylether drastically decreases, making more evident the previouslyshown problems for the recovery of the unreacted monomer from the rawpolymerization products or from the polymer itself (U.S. Pat. No.4,487,903-EP 130,052). In some cases, where the monomer cannot becompletely removed by simple stripping under vacuum, more washings mustthen be carried out with fluorinated solvents to completely eliminatethe unreacted vinyl ethers from the polymeric mass.

The perfluoromethylvinylether (MVE) is used as comonomer in plastomericfluoropolymers and, at higher concentrations, also in elastomericfluoropolymers. In particular, in EP 633,257 and EP 633,274 MVE ispolymerized with TFE in the presence of small amounts of PVE or dioxolesto obtain polymers with improved flex life.

The amorphous copolymers of TFE with perfluoromethylvinylether have aT_(g) around 0° C. or slightly lower (Maskornik, M. et al. “ECD-006Fluoroelastomer—A High Performance Engineering Material”. Soc. PlastEng. Tech. Pao. (1974), 20, 675-7).

The extrapolated T_(g) value of the MVE homopolymer is about −5° C. (J.Macromol. Sci.-Phys., B1(4), 815-830, December 1967).

In U.S. Pat. Nos. 5,296,617 and 5,235,074 there is described thereaction of hypofluorite, CF₂(OF)₂, with unsaturated products, whichcontemporaneously leads to the formation of the dioxolane derivative andto the fluorinated olefin. Patent EP 683,181 describes the reactivity ofCF₂(OF)₂ towards olefins, leading to the formation of linear reactionproducts between one hypofluorite molecule and two molecules of the sameolefin, producing symmetric dienes.

The Applicant has surprisingly and unexpectedly found that it ispossible to solve the above mentioned technical problems by usingspecial fluoro vinyl ethers that are furthermore easily synthesized by acontinuous process.

An object of the present invention is fluorovinyl ethers of generalformula:CFX═CXOCF₂OR   (I)wherein R is a C₂-C₆ linear, branched or C₅-C₆ cyclic (per)fluoroalkylgroup, or a C₂-C₆ linear or branched (per)fluoro oxyalkyl groupcontaining from one to three oxygen atoms. When R is a fluoroalkyl orfluorooxyalkyl group as above defined, it can contain 1 or 2 atoms, thesame as or different from each other, selected from the following: H,Cl, Br, I; X═F, H. The term (per)fluoro refers to a molecule in whichfrom one up to all of the hydrogens capable of being replaced withfluorine are replaced with fluorine.

The fluorovinyl ethers of general formula:CFX═CXOCF₂OCF₂CF₂Y   (II)wherein Y═F, OCF₃ or X as above defined, are preferred among thecompounds of formula (I).

The perfluorovinyl ethers of formula:CF₂═CFOCF₂OCF₂CF₂Y   (III)wherein Y is as above defined, are particularly preferred. For examplethe perfluorovinyl ether of formula IVCF₂═CFOCF₂OCF₂CF₃   (IV)can be mentioned as particularly preferred perfluorovinyl ethers.

Surprisingly, the vinyl ethers according to the invention show theadvantages reported hereinafter with respect to the known vinyl ethers.

The advantages can be attributed to the —OCF₂O— unit directly bound tothe ethylene unsaturation.

The Tg lowering obtained with the vinyl ethers of the invention isconnected to the presence of the (—OCF₂O—) unit directly bound to theunsaturation. The Tg lowering is so surprisingly evident that it can bedefined as a primary effect.

In fact, if the vinylether of the invention having two oxygen atoms isused:CF₂═CF—O—CF₂—O—CF₂CF₃   (MOVE 1)the Tg is clearly lower compared to the Tg of the polymer from PVECF₂═CF—O—CF₂CF₂CF₃   (PVE)and to the polymer from the vinyl ether having the same formula, butwith the second oxygen atom in a different position and not having thecharacteristic unit (—OCF₂O—), i.e.CF₂═CF—O—CF₂CF₂—O—CF₃   (β-PDE)It is surprising to notice that with respect to MVECF₂═CF—O—CF₃the β-PDE vinyl ether does not give any advantage as regards Tg of theresulting polymers.

On the contrary, the primary effect of the (—OCF₂O—) unit is very clearin the polymers of the vinyl ethers of the present invention (MOVE).

It has surprisingly been found that the (—OCF₂O—) unit bound to theethylene unsaturation of the vinyl ethers of the invention drasticallyincreases the vinylether reactivity, reducing the rearrangements toC(O)F which cause instability in the resulting polymer.

The advantages of the present invention can be summarized as follows.

The reactivity of the new monomers allows preparation of copolymershaving a high MW (molecular weight) with a very low content ofcarboxylic groups or derivatives thereof such as —C(O)F or —COO—. Thecarboxylic group content in the copolymer of a monomer of the presentinvention with TFE is about 10 times lower than that of a copolymerprepared under the same conditions but using perfluoropropyl vinyl ether(PVE) instead of the inventive fluorovinyl ethers of the presentinvention (see the Examples). As noted, a lower content of carboxylicgroups, or of the corresponding derivatives (amides, esters, etc.)results in more stable polymers.

The reactivity of the monomers of the present invention is surprisinglyhigh (see the homopolymerization Examples). The fluorovinyl ethers ofthe invention can be used as comonomers both in plastomeric(per)fluoropolymers (containing crystalline domains) and in elastomeric(per)fluoropolymers. To obtain plastomeric polymers the amount of thevinylether of the invention must be such to allow and lead to theformation of crystalline domains, generally <1000 by moles. The presenceof crystalline domains can be determined by DSC. To obtain amorphouspolymers the amount of the vinylether of the invention must be such tolead to the disappearance of the crystalline domains. The skilled man inthe art can easily find the amount of the vinylether of the inventionwhich is required for obtaining said results.

The novel fluorovinyl ethers of the present invention can be used inamounts as low as about 0.1% on a mole basis. Generally the amount ofthe vinyl ether for obtaining amorphous polymers is higher than 10% bymoles (i.e. 10 mole %), preferably in the range from about 15 to 20% bymoles, or higher. In the case of copolymers having a high content ofvinyl ether monomer, the low temperature properties (e.g. T_(g)) of thepolymers of the invention are clearly better compared to copolymershaving the same MVE content (see the Examples) and also, surprisingly,compared to copolymers where the perfluorovinyl ether of equal number ofoxygen atoms does not have a —OCF₂O group directly bound to theunsaturation, as in the case of the CF₂═CFOCF₂CF₂OCF₃ (β-PDE) (see theExamples).

The use of the monomers of the present invention in the polymerizationreactions with fluoroolefins allows substantial and contemporaneousimprovements over two important disadvantages of the prior art: therecovery of the unreacted vinylether and the polymer instability due tothe presence of carboxylic end groups. A further advantage of thefluorovinyl ethers of the invention, as hereinafter illustrated, is thattheir preparation is carried out on a continuous basis by a limitednumber of steps. Furthermore, the raw materials used are inexpensive.The following raw materials can for example be mentioned CF₂(OF)₂,CF₂═CF₂, CF₂═CFOCF₃, CHCl═CFCl, CFCl═CFCl, CF₂═CFCl, CF₂═CFH, CF₂═CH₂,CHCl═CHCl and other olefins. The use of these reactants is specified inthe synthesis process of the vinyl ethers of the invention.

When used in connection with a quantity the term about refers to suchnormal variation in that quantity as would be expected by the skilledartisan.

As used herein, essentially free of crystalline zones or regions meansthat crystallinity is not detected by, for example, DSC, under typicalordinary conditions as would be used by the skilled artisan in routineexperiments.

Polymers, homopolymers and copolymers are obtainable by polymerizing thefluorovinyl ethers of general formula (I)-(IV) alone or with at leastone other monomer.

By copolymer,sa polymer containing units derived from the vinyl ether ofthe invention and one or more comonomers, is meant.

Preferred comonomers are fluorinated compounds having at least onepolymerizable double bond, C═C, optionally containing hydrogen and/orchlorine and/or bromine and/or iodine and/or oxygen.

Other comonomers that can be copolymerized with the fluorovinyl ethersof the present invention are non fluorinated C₂-C₈ olefins, i.e.olefinically unsaturated hydrocarbons such as ethylene, propylene, andisobutylene.

Among the usable comonomers the following can be mentioned:

-   -   C₂-C₈ perfluoroolefins, such as tetrafluoroethylene (TFE),        hexafluoropropene (HFP), hexafluoroisobutene;    -   C₂-C₈ hydrogenated fluoroolefins, such as vinyl fluoride (VF),        vinylidene fluoride (VDF), trifluoroethylene, CH₂═CH—R² _(f)        perfluoroalkylethylenes, wherein R² _(f) is a C₁-C₆        perfluoroalkyl group;    -   C₂-C₈ chloro- and/or bromo- and/or iodo-fluoroolefins, such as        chlorotrifluoroethylene (CTFE) and bromotrifluoroethylene;    -   CF₂═CFOR² _(f) (per)fluoroalkyl vinyl ethers (PAVE), wherein R²f        is a C₁-C₆ (per)fluoroalkyl group, for example a        trifluoromethyl, bromodifluoromethyl or a heptafluoropropyl        group;    -   CF₂═CFOX^(a) (per)fluoro-oxyalkylvinyl ethers, wherein X^(a) is:        a C₁-C₁₂ alkyl, or a C₁-C₁₂ oxyalkyl group, or a C₁-C₁₂        (per)fluorooxyalkyl group having one or more ether groups, for        example perfluoro-2-propoxypropyl.    -   sulphonic monomers having the structure CF₂═CFOX^(b)SO₂F,        wherein X^(b)═CF₂CF₂, CF₂CF₂CF₂, CF₂CF(CF₂X^(c)) wherein        X^(c)═F, Cl, Br.

The process for preparing fluorinated polymers according to the presentinvention can be carried out by polymerization in organic solvent asdescribed in U.S. Pat. Nos. 4,864,006 and 5,182,342, herein incorporatedby reference. The organic solvent is selected from the group includingchlorofluorocarbons, perfluoropolyethers, hydrofluorocarbons andhydrofluoroethers.

The process for preparing the polymers of the present invention can alsobe carried out by polymerization in aqueous emulsion according to wellknown methods in the art, in the presence of a radical initiator whichcan be selected from, for example: inorganic peroxides (for examplealkaline metal or ammonium persulphates, perphosphates, perborates orpercarbonates), optionally in combination with ferrous, cuprous orsilver salts, or of other easily oxidizable metals; organic peroxides(for example, disuccinylperoxide, terbutylhydroperoxide,diterbutylperoxide); azocompounds (see U.S. Pat. Nos. 2,515,628 and2,520,338, herein incorporated by reference). It is also possible to useorganic or inorganic redox systems, such as ammonium persulphate/sodiumsulphite or, hydrogen peroxide/aminoiminomethansulphinic acid tomentioned just a few.

Surfactants of various types are usually present in the reaction medium,among which the fluorinated surfactants of formula:R³ _(f)—X⁻M⁺wherein R³ _(f) is a C₅-C₁₆ (per)fluoroalkyl chain or a(per)fluoropolyoxyalkyl chain, X⁻ is —COO⁻ or —SO₃ ⁻, M⁺ is selectedfrom H⁺, NH₄ ⁺, and an alkali metal ion are particularly preferred.Among the most commonly used surfactants, ammonium perfluorooctanoate,(per) fluoropolyoxyalkylenes terminated with one or more carboxylicgroups, etc. can be mentioned.

During the polymerization, known iodinated a brominated chain transferagents can be added to the reaction medium. It is also possible to useas chain transfer agents alkaline or alkaline earth metal iodides orbromides, according to U.S. Pat. No. 5,173,553, herein incorporated byreference.

Other chain transfer agents are mentioned in U.S. Pat. No. 4,766,190,herein incorporated by reference.

Crosslinking of the amorphous polymers of the present invention can becarried out according to methods well known in the art. When, forexample, one of the comonomers is vinylidene fluoride or vinyl fluoride,curing can be carried out with polyamines or aromatic polyols in thepresence of suitable catalysts (accelerants) as described in U.S. Pat.Nos. 3,876,654 and 4,259,463. When the monomer is perfluorinated, onegenerally uses in the copolymerization, in amounts lower than or equalto 3%, a comonomer having a reactive site that includes, for example,Br, I, CN, OC₆F₅, COOR^(a) (wherein R^(a) is an alkyl from 1 to 5 carbonatoms), or double bonds as described in U.S. Pat. No. 5,268,405. Whenthe polymer contains Br or I, it is cured in the presence of a peroxideor a polyunsaturated compound as described in U.S. Pat. Nos. 4,948,852,4,948,853 and 4,983,60, and EP 683,149.

Another object of the present invention is the synthesis process of thenew (per)fluorovinyl ethers, which comprises the reaction ofhypofluorite CF₂(OF) 2 with fluorinated olefin of formula R₁R₂C═CR₃R₄ togive a first intermediate hypofluorite F—CR₁R₂—CR₃R₄—OCF₂OF, thesubsequent reaction of said compound with a second fluorinated olefin offormula R₅R₆C═CR₇R₈ to give second intermediateF—CR₁R₂—CR₃R₄—OCF₂O—CR₇R₆—CR₇R₈—F, which is converted by an eliminationreaction such as dehalogenation or dehydrohalogenation to the novelperfluorovinyl ethers.

The general scheme of the synthesis is as follows:a) CF₂(OF)₂+R₁R₂C═CR₃R₄→F—CR₁R₂—CR₃R₄—OCF₂OF   (VI)b)F—CR₁R₂—CR₃R₄—OCF₂OF+R₅R₆C²═C¹R₇R₈→F—CR₁R₂—CR₃R₄—OCF₂O—C²R₅R₆—C¹R₇R₈—F  (VII)dehalogenation./c) F—CR₁R₂—CR₃R₄—OCF₂O—C²R₅R₆—C¹R₇R₈—F→,/dehydrohalogenation.CFX═CXOCF₂OR   (I)In this synthesis scheme, with reference to the formula of the compound(VII), R₁, R₄, are the same or different and are H, F; R₂, R₃; are thesame or different and are H or Cl subject to the following conditions;(1) when the final reaction is to be a dehalogenation, R₂═R₃ ═Cl; (2)when the final reaction is to be a dehydrohalogenation one of the twosubstituents R₂ or R₃ is H and the other is Cl. Further R₅, R₆, R₇, R₈are: F, or one of them is a C₁-C₄ linear or branched perfluoroalkylgroup or a C₁-C₄ linear or branched perfluorooxyalkyl group containingfrom one to three oxygen atoms, or R₅ and R₇ or R₆ and R₈ are linked toeach other to form with C² and C¹ a C₅-C₆ cyclic perfluoroalkyl group.Also, when one of the R₅ to R₈ radicals is a C₂-C₄ linear or branchedfluoroalkyl or a C₂-C₄ linear or branched fluorooxyalkyl groupcontaining from one to three oxygen atoms, one or two of the other R₅ toR₈ are F and one or two of the remainders, which can be the same as ordifferent from each other, are selected from H, Cl, Br and; when twosubstituents are selected from H, Cl, Br or I, they are both linked tothe same carbon atom. When R₅ and R₇ or R₆ and R₈ are linked each otherto form with C² and C¹ a C₅-C₆ cycle fluoroalkyl group, one of the twofree substituents R₆, R₈ or R₅, or R₇ is F and the other is selectedfrom H, Cl, Br, Iodine.

The fluoroalkene used in reaction a) is replaceable with that of thesubsequent reaction b). In this case the meanings defined for thesubstituents of the R₁-R₄ group, and respectively of the R₅-R₈ group,are interchangeable each other, with the proviso that the position ofeach radical of each of the two groups R₁-R₄ and R₅-R₈ with respect to—OCF₂O— on the chain of the intermediate compound (VII), is the same aswould be if the synthesis takes place according to the above reportedscheme and the two olefins each react in the considered steps.

In the first reaction a) of the above illustrated scheme, a hypofluoritegas flow CF₂(OF)₂, optionally suitably diluted with an inert fluid,comes into contact (i.e. is contacted with), in a suitable reactor withoutlet, on the bottom of the same (first reactor), with the R₁R₂C═CR₃R₄olefin, optionally diluted in an inert fluid and preferably in gas flow,to allow the chemical reaction a) with formation of the intermediatehypofluorite (VI). To maintain the reaction stoichiometry, the reactantsmust be introduced into the reactor in an approximately unitary molarratio, or with an excess of CF₂(OF)₂. The residence time of the mixturein the reactor can range from about a few hundredths of second (e.g.about 0.05 seconds) up to about 120 seconds depending on the olefinreactivity, the reaction temperature, and the presence of optionalreaction solvents.

The reaction temperature can range from about −40° to about −150° C.,preferably from about −800 to about −130° C.

The compound (VI) usually is not separated from the reaction product andit is transferred in a continuous way to the subsequent reactiondescribed in step b).

The mixture of the products coming out from the first reactor can beheated to room temperature before being fed into the second reactor.

In the second reaction b), the second olefin R₅R₆C═CR₇R₈, pure or insolution, reacts with the product obtained in the first reaction withformation of compound (VII).

The olefin can be fed in a continuous way, so as to maintain itsconcentration constant in the reactor; except for that normal variationas would be expected by the skilled artisan. The temperature of thereaction b) can range from about −20° to about −130° C., preferably fromabout −50° to about −100° C. The olefin concentration is higher than orequal to about 0.01M, preferably the concentration is higher than 3M,more preferably the olefin in a highly purified state is used.

The solvents useful in steps a) and b) are perfluorinated orchlorohydrofluorinated solvents or hydrofluorocarbons. Examples of saidsolvents are: CF₂Cl₂, CFCl₃, CF₃CFH₂, CF₃CF₂CF₃, CF₃CCl₂H, CF₃CF₂Cl.

In reaction c), the compound (VII), after distillation from the reactionproduct, is subjected to dechlorination or to dehydrochlorination as thecase may be to obtain the vinyl ethers of formula (I). This last stepcan be carried out by using reactions widely described in the-prior art.The suitable selection of the substituents R₁ to R₈ in the two olefinsused in the synthesis allows one to obtain the vinyl ethers of thepresent invention.

Another object of the invention is a process wherein a hypofluorite offormula X₁X₂C(OF)₂ wherein X₁ and X₂ are the same or different and are For CF₃, and two fluoroalkenes of formulas, respectively, R^(A) ₁R^(A)₂C═CR^(A) ₃R^(A) ₄ and R^(A) ₅R^(A) ₆C═CR^(A) ₇R^(A) ₈, wherein R^(A)₁-R^(A) ₈ are the same or different and are F, H, Cl, Br, I, —CF₂OSO₂F,—SO₂F, —C(O)F, C₁-C₅ linear or branched perfluoroalkyl oroxyperfluoroalkyl group, are reacted according to steps a) and b),excluding the dehalogenation or dehydrohalogenation step, to obtaincompounds of general formula (VIII)F—CR^(A) ₁R^(A) ₂—CR^(A) ₃R^(A) ₄—OCF₂O—CR^(A) ₅R^(A) ₆—CR^(A) ₇R^(A)₈—F.   (VIII)

The following Examples are reported to illustrate the invention and theydo not limit the scope of the same.

In the Examples the thermogravimetric analysis (TGA) is carried out at aheating rate of 10° C./min.

EXAMPLE 1 Synthesis of CF₃CF₂CF₂OCFClCF₂Clperfluoro-1-2,dichloro-3,5-dioxaheptane

The reactor used is of the cylindrical type, with a total volume ofabout 300 ml and is equipped with magnetic dragging mechanical stirrer,turbine with recycle of the reacting gas placed at 20 cm from thereactor top, internal thermocouple, two internal copper pipes for thereactant feeding which end at about 1 mm from the turbine, and productoutlet from the bottom. In the reactor, the internal temperature ofwhich is maintained at −114° C., 1.1 1/h (liters/hour) of CF₂(OF)₂ and3.3 1/h of He are introduced through one of the two inlet pipes. A flowof 1.1 1/h of CF₂═CF₂ and 0.7 1/h of He is maintained through the secondinlet pipe. Feeding is continued for 6.6 hours.

The residence time of the transport gas in the reaction zone, comprisedof the space between the outlet of the two feeding pipes in the reactorand the inlet of the discharge pipe, is of about 4 sec.

From the reactor bottom the reaction products are brought to roomtemperature and the flow of gaseous mixture, monitored by gaschromatography, is fed in a continuous way, under mechanical stirring,into a second reactor having a 250 ml volume maintained at thetemperature of −70° C. and equipped with mechanical stirrer,thermocouple, dipping inlet for the reacting mixture, outlet with headof inert gas. The reactor contains 72.6 g of dichlorodifluoroethyleneCFCl═CFCl.

At the end of the addition of reacting gases into the second reactor,the reaction raw material is distilled by a plate column at atmosphericpressure, collecting 41.5 g of the desired product (boiling point 91°C.).

The yield of perfluoro-1,2 dichloro-3,5-dioxaheptane, calculated withrespect to CF₂(OF)₂, is 36%.

Characterization of perfluoro 1,2 dichloro-3.5-dioxaheptane.

Boiling point at atmospheric pressure: 91° C. ¹⁹F-NMR spectrum in p.p.m.(with respect to CFCl₃ at 0):

-   -   −51.3/−53.0 (2F, O—CF₂—O); −70.6/−72.6 (2F, C—CF₂Cl);    -   −78.0−78.4 (1F, O—CFCl—C); −87.8 (3F, CF₃—C);    -   −90.2/−91.8 (2F, C—CF₂—O).

Mass spectrum (E.I. electronic impact), main peaks and respectiveintensities:

-   -   69 (48.6%); 119 (84.3%); 151 (76.86); 153 (69.8%); 185 (100%).

IR spectrum (cm⁻¹) intensity: (w)=weak, (m)=medium, (s)=strong,(vs)=very strong:

-   -   1407.3 (w); 1235.8 (vs); 1177.7 (vs); 1097.5(vs); 1032.2 (s);        929.3 (w); 847.9 (m).

EXAMPLE 2 Synthesis of CF₃OCF₂CF₂OCF₂OCFClCF₂Clperfluoro-1,2-dichloro-3,5,8-trioxanonane (isomer A) and ofCF₃OCF(CF₃)OCF₂OCFClCF₂Clperfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctane (isomer B)

In a reactor identical to that used in Example 1, maintained at the sametemperature of −114° C., 1.55 1/h of CF₂(OF)₂ and 4.5 1/h of He areintroduced through one of the two inlet pipes; through the second inletpipe 1.4 1/h of CF₂═CF—OCF₃ and 0.7 1/h of He are fed for 4.5 hours.

The residence time of the transport gas in the reaction zone comprisedbetween the reactor outlet and the end of the two feeding pipes is ofabout 3 sec.

On the reactor bottom the reaction products are brought to roomtemperature and the gaseous mixture flow, monitored by gaschromatography, is fed in a continuous way, under mechanical stirring,into a second reactor identical to the one used for the same step inExample 1. Inside, where a temperature of −70° C. is maintained, thereare 51 g of dichlorofluoroethylene CFCl═CFCl.

At the end of the addition of the reacting gases into the secondreactor, the reaction raw material is distilled by a plate column at thereduced pressure of 250 mmHg. 50 g of a mixture formed by two isomers,respectively, isomer A) perfluoro-1,2-dichloro-3,5,8-trioxanonane andisomer 3) perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctane arecollected.

The mixture composition is determined by gas chromatography and is asfollows: isomer A 79%, isomer B 21%. The molar yield of A+B with respectto the CF₂(OF)₂ used is 38%. The molar yield of A+B with respect to theused perfluoromethylvinylether is 42%. The isomers have been separatedby preparative gas chromatography.

Characterization of Products A and B

Mixture boiling point (A 79%, B 21%) at the reduced pressure of 250mmHg: 82° C.

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of the isomer A:

-   -   −50.6/−52.4 (2F, O—CF₂—O); −70.0/−71.8 (2F, C—CF₂Cl);    -   −77.7 (1F, O—CFCl—C); −55.3/−55.6 (3F, CF₃—OC);    -   −90.7/−91.1 (2F, C—OCF₂—C); −90.2/−90.6 (2F, C—OC—CF₂OCOC).

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of isomer B:

-   -   −50.0/−52.1 (2F, O—CF₂—O) −70.0/−71.8 (2F, C—CF₂Cl);    -   −77.9 (1F, O'CFCl—C); −54.6/−54.9 (3F, CF₃OC):    -   −85.7/−86.1 (3F, OC (CF₃)0); −100.3/−101.0 (1F, OCF(C)O).

Mass spectrum (electronic impact) main peaks and respective intensities:

-   -   Product A: 69 (50); 119 (100); 151 (50); 185 (42); 251 (38);    -   Product B: 69 (96); 97 (50); 135 (42); 151 (92); 185 (100).

IR spectrum (cm⁻¹), intensity of the mixture A 79%, B 21%

-   -   ((w)=weak, (m)=medium, (s)=strong, (vs)=very strong): 1388 (w);        1288 (vs); 1233 (vs); 1151 (vs); 1104 (vs); 1032 (s); 846 (m);        685 (w)

EXAMPLE 3 Synthesis of CF₃OCF₂CF₂OCF₂OCHClCHFClperfluoro-1,2-dichloro-1,2-dihydro-3,5,8-trioxanonane (isomer C) andCF₃OCF(CF₃)OCF₂OCHClCHFClperfluoro-1,2-dichloro-1,2-dihydro-3,5,7-trioxa-6-methyloctane (isomerD)

In a reactor identical to that used in Example 1, maintained at thetemperature of −112° C., 1.55 1/h of CF₂(OF)₂ and 4.5 1/h of He areintroduced through one of the two inlet pipes. Through the second inletpipe 1.4 1/h of CF₂═CF—OCF₃ and 0.7 1/h of He are introduced for 5hours.

The residence time of the transport gas in the reaction zone comprisedbetween the reactor outlet and the end of the two feeding pipes is about3 sec.

From the reactor bottom the reaction products are brought to roomtemperature and the gaseous mixture flow, monitored by gaschromatography, is fed in a continuous way, under mechanical stirring,into a second reactor identical to the one used for the same step inExample 1. Inside the second reactor the temperature is −70° C. andthere are 50 g of 1,2-dichloroethylene CClH═CClH and 50 g of CFCl₃.

At the end of the addition of the reacting gases into the secondreactor, after distillation of the solvent at room pressure, thereaction raw material is distilled through a plate column at the reducedpressure of 100 mmHg. 43.5 g of the mixture of the desired products(isomer C 78%, isomer D 22%, determined by gas chromatography) arecollected. The molar yield of C+D with respect to the used CF₂(OF)₂ is33%. The isomers have been separated by preparative gas chromatography.

Characterization of Products C and D

Mixture boiling point (78%, D 22%) at the reduced pressure of 100 mmHg:71° C.

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of the isomer Cperfluoro-1,2-dichloro-1,2-dihydro-3,5,8-trioxanonane:

-   -   −56. 0/−57.2 (2F, O—CF₂—O); −143.2/−146.0 (1F, C—CHFCl);    -   −55.8 (3F, CF₃—OC); −91.0/−91.4 (2F, C—OCF₂—C);    -   −90.3/−90.5 (2F, C—OC—CF₂OCOC).

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of the isomer Dperfluoro-1,2-dichloro-1,2-dihydro-3,5,7-trioxa-6-methyloctane:

-   -   −56.0/−57.2 (2F, O—CF₂—O); −143.2/−146.0 (1F, C—CHFCl);    -   −54.9/−55.1 (3F, CF₃—OC); −86.2/−86.3 (3F, OC(CF₃)0);    -   −100.5/−101.0 (1F, OCF(C)O).

¹H spectrum-in p.p.m. (with respect to TMS) of the isomers C and D:6.28/6.05 (1H —CHFCl); 6.02/5.95 (1H —CHCl—)

Mass spectrum (electronic impact), main peaks and respective intensities%: 69 (84); 119 (100); 185 (51.1); 251 (84); 281 (15.8); 283 (4.8); 347(5.7); 349 (1.7)

IR spectrum (cm⁻¹) intensity ((w)=weak, (m)=medium, (s)=strong,(vs)=very strong): 3001.0 (w); 2920.9 (w); 2850.9 (w); 1286.3 (vs);1233.7 (vs); 1125.5 (vs); 1081.8 (s); 1047.9 (s); 815.9 (m); 766.3 (m).

EXAMPLE 4 Dehalogenation of perfluoro 1,2-dichloro-3,5-dioxaheptane

In a 25 ml three-necked flask, equipped with mechanical stirrer,thermometer, dropping funnel, distillation column equipped with waterrefrigerant and collecting trap maintained at −78° C. and connected to amechanical vacuum pump, 150 ml of DMF, 15 g of powdered Zn, 0.5 g ofK₂CO₃, and 100 mg of 12 are introduced. The internal temperature isbrought to 80° C. and 50 g of perfluoro-1,2-dichloro-3,5-dioxaheptaneare added dropwise. When the addition is over, the mixture is allowed toreact for about 30 minutes. At the end, the internal pressure isgradually brought from 760 mmHg to 300 mmHg. After about 20 minutes, thecollecting trap containing 34.2 g of perfluoro-3,5-dioxa-1-heptene(MOVE 1) is disconnected.

The dehalogenation yield is 85%.

Characterization of perfluoro-3,5-dioxa-1-heptene (MOVE 1)

Boiling point at atmospheric pressure: 41.9° C.

¹⁹F-NMR spectrum in p.p.m. with respect to CFCl₃ at 0:

-   -   −56.8 (2F, O—CF₂—O); −87.2 (3F, CF₃—C)    -   −90.6 (2F, C—CF₂—O) ; −114 (1F, O—C═C—F)    -   −121.8 (1F, O—C═CF); −137 (1F, O—C—F═C);

Mass spectrum (electronic impact), main peaks and respectiveintensities: 69 (66.5%); 119 (100%); 147 (83.4%); 185 (89.4%); 216(67.3%); 282 (8.2%).

IR spectrum (cm⁻¹) intensity ((w)=weak, (m)=medium,(s)=strong, (vs)=verystrong: 1839.5 (m); 1407.6 (w); 1307.4 (vs); 1245.8 (vs); 1117.4 (vs);907.2 (m); 846.0 (m).

EXAMPLE 5 Dehalogenation of the isomer mixture A+B obtained in Example 2(perfluoro-1,2-dichloro-3,5,8-trioxanonaneCF₃OCF₂CF₂CF2OCFClCF₂Cl+perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctaneCF₂OCF(CF₃)OCF₂OCFClCF₂Cl)

In a 250 ml flask equipped as described in the previous Example 4, 110ml of DMF, 10 g of Zn in powder and 0.3 ml of Br₂ are introduced. Theinternal temperature is brought to 75° C. and 30.3 g of the binarymixture A+B separated in the previous Example 2 are added dropwise. Whenthe addition is over, the mixture is allowed to react for about 3 hours.At the end, the internal pressure is gradually lowered from 760 mmHg to200 mmHg at −79° C. After about 30 minutes the collecting trap isdisconnected. The trap contents, which are washed with water, arerecovered. Twenty-four grams of a mixture formed of 79% (gaschromatographic determination) perfluoro-3,5,8-trioxa-1-nonene (MOVE '2)CF₃OCF₂CF₂OCF₂OCF═CF₂ (isomer A′), and 21%perfluoro-3,5,7-trioxa-6,methyl-1 octene (MOVE 2a)CF₃OCF(CF₃)OCF₂O—CF═CF₂ (isomer B′) are obtained. The mixture is thenseparated by preparative gas chromatography.

Characterization of Products A′ and B′

Boiling range of the isomer mixture at atmospheric pressure: 72.5°-74.5°C.

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of the isomerA′: −55.9 (3F, CF₃—O); −56.9 (2F, O—CF₂—O) ; −90.8 (2F, C—CF₂—O); −91.2(2F, O—CF₂—C); −114 (1F, O—C═C—F); −121.8 (1F, —O—C═CF); −137 (1F,O—CF═C)

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of the isomerB′: −55.9 (3F, CF₃—O); −56.2 (2F, O—CF₂—O); −86.4 (3F, CF₃—C); −100.9(1F, CF; −114 (1F, O—C═C—F); −122 (1F, O—C═CF); −137 (1F, O—CF═C).

Mass spectrum (electronic impact), main peaks and respective intensitiesof the isomer A′: 69 (74); 81 (18); 119 (100); 147 (59); 185 (26); 251(21);

Mass spectrum (electronic impact), main peaks and respective intensitiesof the isomer B′: 69 (80); 81 (37); 97 (47); 119 (36); 147 (100); 185(19).

IR spectrum (cm⁻¹) intensity ((w)=weak, (m)=medium, (s)=strong,(vs)=very strong): 1839 (m); 1343 (s); 1248 (vs); 1145 (vs); 918 (m);889 (m).

EXAMPLE 6 Dehalogenation of the isomers C+D mixture obtained in Example3 (CF₃OCF₂CF₂OCF₂OCHClCHFClperfluoro-1,2-dichloro-1,2-dihydro-3,5,8-trioxanonane (isomerC)+CF₃OCF(CF₃) OCF₂OCHClCHFClperfluoro-1,2-dichloro-1,2-dihydro-3,5,7-trioxa-6-methyloctane (isomerD))

In a 500 ml three-necked flask, equipped with mechanical stirrer,thermometer, dropping funnel, distillation column having a waterrefrigerant and a collecting trap maintained at the temperature of −78°C., 250 ml of DMF, 30 g of zinc powder, and 300 mg of I₂ are introduced.

The temperature is brought to 100° C. and 56.9 g of the isomer mixtureobtained in Example 3 are added dropwise.

When the addition is, over the reactor internal temperature is broughtto 120° C. and stirring is maintained for 24 hours. At the end, thereaction product, which contains traces of solvent and which iscollected in the trap maintained at −78° C., is distilled. After washingwith water, 35 g of a mixture ofperfluoro-1,2-dihydro-3-5-8-trioxa-1-nonene (isomer C′, 79% by mole) andof perfluoro-1,2-dihydro-3-5-7-trioxa-5-methyl-1-octene (isomer-D′, 21%by mole) is recovered. The isomers are separated by preparative gaschromatography.

The dehaloagenation reaction yield is 76%.

Characterization of Products C′ and D′

Boiling range of the mixture of-isomers C′79%, D′ 21% at atmosphericpressure: 90.0°-92.0° C.

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of the isomer C′perfluoro-1,2-dihydro-3,5,8-trioxa-1-nonene:

-   -   −55.7 (3F, CF₃—O); −57.3 (2F, O—CF₂—O); −90.9 (2F, C—CF₂—O);        −91.2 (2F, O—CF₂—C); −149.3/−150.0 (1F, O—C═C—F).

¹⁹F-NMR spectrum in p.p.m. (with respect to CFCl₃ at 0) of the isomer D′perfluoro-1,2-dihydro-3,5,7-trioxa-6-methyl-1-octene: −55.0 (3F, CF₃—O);−56.9 (2F, O—CF₂—O); −86.2 (3F, CF₃—C); −101.0 (1F, CF) −149.3/−150, 0(1F, O—C═C—F)

Mass spectrum (electronic impact), main peaks and respective intensities%: 69 (82); 119 (100); 185 (29); 246 (25); 251 (20); 312 (43).

IR spectrum (cm⁻¹) intensity of the isomer mixture (C′ 79%, D′ 21%)((w)=weak, (m)=medium, (s)=strong, (vs)=very strong): 3140 (w); 1722(w); 1695 (w); 1402 (m); 1281 (vs); 1237 (vs); 1147 (vs); 1106 (vs);1030 (m).

EXAMPLE 7 Homopolymerization of perfluoro-3 5-dioxa-1-heptene (MOVE 1)

In a glass reactor for polymerization, having a 20 ml volume, equippedwith magnetic stirrer and with an inlet for the reactant feeding anddischarge, 60 μl of perfluoropropionylperoxide at 3%. by weight inCFCl₂CF₂Cl and 3 g of MOVE 1 are sequentially introduced. The so-chargedreactor is-brought to the temperature of −196° C., evacuated, brought toroom temperature. The cooling-evacuation procedure is repeated. At theend of the degassing operations the reactor is thermostated at thetemperature of 30° C. and the mixture is allowed to react under theseconditions for two days with magnetic stirring.

The reaction raw material which is finally recovered appears as aslightly viscous, transparent, colourless and homogeneous solution.

After distillation of the unreacted monomer and subsequent strippingunder vacuum at 150° C. for 3 hours, 180 mg of the polymer areseparated.

The IR analysis of the obtained polymer shows that, in the spectrum,absorption bands in the region of fluorinated double bonds are absent.

The ¹⁹F-NMR analysis carried out on the polymer dissolved in C₆F₆ is inaccordance with the homopolymer structure having a molecular weight of50,000. The analysis does not show the presence of unreacted monomer.

The DSC thermogram does not show any melting endothermic curve,wherefore the polymer is amorphous. The polymer T_(g), determined byDSC, is −35.4° C. The thermogravimetric analysis (TGA) shows a weightloss of 2% at 332° C. and of 10% at 383° C.

EXAMPLE 8 Copolymer between perfluoro-3,5,8-trioxa-1-noneneCF₃OCF₂CF₂OCF₂OCF═CF₂ (MOVE 2) and perfluoro-3,5,7-trioxa-6,methyl-1-octene CF₃OCF(CF₃ )OCF₂O—CF═CF₂ (MOVE 2a)

In a reactor having the same characteristics as that described inExample 7, 150 μl of perfluoropropionylperoxide at 3% by weight inCFCl₂CF₂Cl and 3.2 g of a mixture prepared according to the process ofExample 5 and containing 83% MOVE 2 and 17% MOVE 2a, are introduced. Thereactor is then evacuated, cooled, and the subsequent reaction carriedout as described in the previous Example 7.

The raw reaction product appears as a slightly viscous, transparent,colourless and homogeneous solution. The unreacted monomers aredistilled and a stripping under vacuum at 150° C. for 3 hours isthereafter carried out. Finally, 350 mg of the polymer are separated.

The IR analysis shows that, in the polymer spectrum, absorption bands inthe region of the fluorinated double bonds are absent.

The ¹⁹F-NMR analysis is in accordance with the copolymer structurehaving an average molecular weight of 35,000 and a MOVE 2/MOVE 2acontent equal to the percentages of the respective monomers in thereacting mixture. Unreacted monomers are not evident.

The DSC thermogram does not show any melting endothermic curve,wherefore the polymer is amorphous. The polymer T_(g), determined byDSC, is −52.6° C. The thermogravimetric analysis (TGA) shows a weightloss of 2% at 280° C. and of 10% at 327° C.

EXAMPLE 9 Crystalline copolymer between MOVE 1 and TFE

A 5 1 steel AISI 316 autoclave with stirrer operating at 650 rpm isused. After evacuation of the autoclave, 3 1 of demineralized water,15.70 g of MOVE 1 and the microemulsion prepared according to theprocedure described in U.S. Pat. No. 4,864,006 are sequentiallyintroduced, so as to have a concentration of 2 g of surfactant/1 ofwater.

The autoclave is heated to 75° C. and then pressurized to 0.32 bar withethane. A gaseous mixture in a molar ratio of 54.55 TFE/MOVE 1 is pumpedby a compressor until internal pressure on the autoclave is 21 absolutebar.

The composition of the gaseous mixture present in the top of theautoclave is analyzed by gas chromatography.

Before the reaction is started, the gaseous phase has the followingmolar percentages of the reactants: 93.16 TFE, 5.5% MOVE 1 and 1.40Ethane. The reaction is triggered by feeding, in a continuous way by ametering pump a 0.0031 molar potassium persulphate solution at a flowrate of 88 ml/h.

The pressure is maintained constant by feeding additional monomermixture. The polymer synthesis is stopped after 742 g of mixture havebeen fed in total.

The reactor is cooled to room temperature, the emulsion is discharged,and coagulation is induced by addition of HNO₃ (65%).

The polymer is separated, washed with water and, dried at 220° C.

The IR analysis shows the presence of very small absorption bands in thecarboxyl zone, the intensity of which is about half of that obtained fora TFE/PVE copolymer film having the same thickness, prepared accordingto the comparative Example 3. The MFI according to ASTMVD 1238-52T was4.4. The polymer therefore is thermally more stable (see the comparativeExample hereunder).

EXAMPLE 10 Amorphous copolymer between MOVE 1 and TFE

In an AISI-316 polymerization reactor having a 40 ml volume, equippedwith magnetic stirring, pressure transducer, and an inlet for thereactant feeding and discharge, 250 μl of perfluoropropionylperoxide at3% by weight in CFCl₂CF₂Cl, 9.8 mmoles of MOVE 1, and 18 mmoles oftetrafluoroethylene are introduced.

The reactor is cooled to −196° C., evacuated, then brought to roomtemperature. The cooling-evacuation procedure is repeated twice.

At the end of the degassing operations, the reactor is thermostated atthe temperature of 30° C. and the reaction mixture maintained undermagnetic stirring. The internal pressure decreases from 6.4 atm to 4.7atm in about 8 hours (reaction time).

After distillation of the unreacted monomers and polymer stripping undervacuum for 3 hours at 150° C., 1,100 mg of polymer are recovered. Thepolymer appears as a transparent and colourless rubber.

By ¹⁹F-NMR analysis of the polymer dissolved with heating in C₆F₆, it isdetermined that the MOVE 1 molar percentage in the polymer is 24%.

The IR analysis does not show, in the polymer spectrum, absorption bandsin the region of the fluorinated double bonds and shows the presence ofvery small absorption bands in the region of the carboxyl bands. Theintensity of these signals, compared to ones in the same region obtainedfrom a film having the same thickness but made of polymer of thecomparative Example 1, is equal to about 1/10 of the latter.

The DSC thermogram does not show any melting endotherm, wherefore thepolymer is amorphous. The T_(g) determined by DSC is −21.4° C.

The TGA shows a weight loss of 2% at 450° C. and of 100 at 477° C. Thepolymer therefore is thermally more stable (see the comparative Examplehereunder) with respect to the comparative Example (see below).

The polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75,is 35.5 ml/g.

EXAMPLE 11 Amorphous copolymer between MOVE 1 and TFE

In an AISI-316 polymerization reactor identical to that described in theprevious Example 10, 250 μl of perfluoropropionylperoxide at 3% byweight in CFCl₂CF₂Cl, 9.75 mmoles of MOVE 1 and 9 mmoles oftetrafluoroethylene are sequentially introduced.

The procedure already described in the previous Example 10 is followeduntil the thermostating step at the temperature of 30° C. under magneticstirring. During the reaction the internal pressure decreases from 3.4atm to 2.9 atm in about 8 hours.

At the end, the unreacted monomers are distilled and the polymer isstripped under vacuum at 150° C. for 3 hours.

480 mg of the polymer are separated.

By ¹⁹F-NMR analysis of the polymer dissolved with heating in C₆F₆, it isdetermined that the MOVE 1 molar percentage in the polymer is 39%.

The IR analysis shows that, in the polymer spectrum, absorption bands inthe region of the fluorinated double bonds are absent.

The DSC thermogram does not show any melting endothermic curve,wherefore the polymer is amorphous. The T_(g) determined by DSC is−29.8° C.

The TGA shows a weight loss of 10a at 435° C.

EXAMPLE 12 Amorphous copolymer between MOVE 1 and CF₂═CH₂

In a polymerization reactor identical to that described in Example 10,250 μl of perfluoropropionylperoxide at 3%. by weight in CFCl₂CF₂Cl, 10mmoles of MOVE 1, and 18 mmoles of VDF are sequentially introduced.

The procedure already described in the previous Example 10 is followeduntil the thermostating step at the temperature of 30° C. under magneticstirring. The internal pressure decreases from 6.8 atm to 5.0 atm duringthe reaction (about 8 hours).

After distillation of the unreacted monomers and subsequent polymerstripping under vacuum at 150° C. for 3 hours, 1,600 mg of the polymerare separated, appearing as a transparent and colourless rubber.

By the ¹⁹F-NMR analysis carried out on the polymer dissolved in C₆F₆ itis determined that the MOVE 1 molar percentage in the polymer is 40%.

The DSC thermogram does not show any melting endothermic curve,wherefore the polymer is amorphous. The T_(g) determined by DSC, is −47°C.

The TGA shows a weight loss of 2% at 428° C. and of 10% at 455° C.

EXAMPLE 13 Amorphous terpolymer MOVE 2/MOVE 2a/TFE

In a polymerization reactor identical to that described in Example 10,100 μl of perfluoropropionylperoxide at 6% by weight in CFCl₂CF₂Cl, 10mmoles of a MOVE 2 (83%) and MOVE 2a (17%) mixture (synthesizedaccording to the process of Example 5), and 18 mmoles oftetrafluoroethylene (TFE) are sequentially introduced.

The procedure already described in the previous Example 10 is thenfollowed until thermostating at the temperature of 30° C. under magneticstirring. The internal pressure decreases from 6.1 atm to 3.9 atm duringthe reaction (about 8 hours).

After distillation of the unreacted monomers and polymer stripping undervacuum at 150° C. for 3 hours, 1,131 mg of the polymer are separated.

By the ¹⁹F-NMR analysis carried out on the polymer dissolved in C₆F₆,the total molar percentage of the MOVE 2+MOVE 2a perfluorovinyl ethersunits in the polymer is 22%; the MOVE 2/MOVE 2a ratio by moles in thepolymer is 83/17 (equal to that of the starting feed mixture).

The presence of unreacted monomers is not evident.

The IR analysis does not show, in the polymer spectrum, absorption bandsin the region-of the fluorinated double bonds, and it shows the presenceof very small absorption bands in the zone of the carboxyl signals. Theintensity of these signals, compared with the similar ones obtained froma film having the same thickness obtained with the polymer of thecomparative Example 1, is equal to about 1/10 of the latter.

The DSC thermogram does not show any melting endotherm, wherefore thepolymer is amorphous. The T_(g) determined by DSC, is −37.5° C.

The TGA shows a weight loss of 10% at 473° C.

The polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75,is 40.0 ml/g.

EXAMPLE 14 Amorphous terpolymer MOVE 2/MOVE 2a/TFE

In a polymerization reactor identical to that described in Example 10,100 μl of perfluoropropionylperoxide at 6% by weight in CFCl₂CF₂Cl, 9.7mmoles of the MOVE 2 (83%) and MOVE 2a (17%) mixture synthesizedaccording to the process of Example 5, and 10 mmoles oftetrafluoroethylene (TFE) are sequentially introduced.

The procedure already described in the previous Example 10 is thenfollowed until the thermostating step at the temperature of 30° C. undermagnetic stirring. The internal pressure decreases from 3.6 atm to 2.7atm during the course of reaction (about 8 hours).

After distillation of the unreacted monomers and polymer stripping undervacuum at 150° C. for 3 hours, 652 mg of polymer are separated.

By the ¹⁹F-NMR analysis carried out on the polymer dissolved in C₆F₆ thetotal molar percentage of units derived from the MOVE 2+MOVE 2aperfluorovinyl ethers in the polymer is 37%; the MOVE 2/MOVE 2a molarratio in the polymer is 83/17 (equal to that of the starting feedmixture).

The presence of unreacted monomers is not evident.

The IR analysis does not show, in the polymer spectrum, absorption bandsin the region of the fluorinated double bonds.

The DSC thermogram does not show any melting endothermic curve,wherefore the polymer is amorphous. The T_(g) determined by DSC, is−44.5° C.

The TGA shows a weight loss of 10% at 451° C.

The polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75,is 16.7 ml/g.

EXAMPLE 15 Amorphous copolymer betweenperfluoro-1,2-dihydro-3,5,8-trioxa-1-nonene (H-MOVE 2) andperfluoro-1,2-dihydro-3,5.7-trioxa-6-methyl-1-octene (H-MOVE 2a) withmolar ratio 88/12

In a reactor identical to that described in Example 7, 200 μl ofperfluoropropionylperoxide at 3% by weight in CFCl₂—CF₂Cl and 3.1 g ofan 88/12 H-MOVE 2/H-MOVE 2a 88/12 mixture are introduced.

The procedure described in Example 7 is followed.

The recovered reaction raw material appears as a slightly viscous,transparent, colourless and homogeneous solution.

After distillation of the unreacted monomer and subsequent strippingunder vacuum at 150° C. for 3 hours, 120 mg of polymer are separated.

The IR analysis of the polymer obtained shows that, in the polymerspectrum, absorption bands in the region of the fluorinated double bondsare absent.

The ¹⁹F-NMR analysis is in accordance with the copolymer structurehaving a content of monomers H-MOVE 2 and H-MOVE 2a equal to the H-MOVE2 and H-MOVE 2a percentages in the reacting mixture. The analysis doesnot show the presence of unreacted monomers.

The DSC thermogram does not show any melting endotherm, wherefore thepolymer is amorphous. The polymer T_(g) determined by DSC, is −58.0°C.The thermogravimetric analysis (TGA) shows a weight loss of 10% at 307°C.

EXAMPLE 16 Terpolymer H-MOVE 2/H-MOVE 2a/TFE

In a reactor similar to that described in Example 10, 100 μl ofperfluoropropionylperoxide at 6% by weight in CFCl₂—CF₂Cl, 5 mmoles of aH-MOVE 2 (88%) and H-MOVE 2a (12%) mixture, and 18 mmoles oftetrafluoroethylene are introduced.

The same procedure described in Example 10 is followed.

At the end of the degassing, the reactor is thermostated at thetemperature of 30° C. under magnetic stirring. The internal pressuredecreases from 6.8 atm to 6.5 atm in about 6 hours (reaction time).

After distillation of the unreacted monomers and polymer stripping undervacuum at 150° C. for 3 hours, 300 mg of the polymer are separated.

By ¹⁹F-NMR analysis of the polymer dissolved under heating in C₆F₆ it iscalculated that the molar percentage (mole %) of units derived from theperfluorovinyl ethers (H-MOVE 2+H-MOVE 2a) contained in the polymer is33%. The H-MOVE 2/H-MOVE 2a molar ratio in the polymer is equal to theH-MOVE 2/H-MOVE 2a molar ratio of the feed mixture. Unreacted monomersare not evident.

The IR analysis does not show, in the polymer spectrum, absorption bandsin the zone of the fluorinated double bonds.

The DSC thermogram does not show any melting endotherm, wherefore thepolymer is amorphous. The T_(g) determined by DSC, is −44.5° C.

The TGA shows a weight loss of 10% at 450° C.

EXAMPLE 1 (COMPARATIVE) Copolymer PVE/TFE

In a polymerization reactor identical to that described in Example 10,250 μl of perfluoropropionylperoxide at 3% by weight in CFCl₂CF₂Cl, 9.8mmoles of PVE, and 18 mmoles of tetrafluoroethylene, are sequentiallyintroduced.

The procedure already described in the previous Example 10 is followeduntil thermostating at the temperature of 30° C. under magneticstirring. The reaction time is eight hours.

After distillation of the unreacted monomers and stripping under vacuumat 150° C. for 3 hours, 540 mg of the polymer are recovered.

By the ¹⁹F-NMR analysis carried out on the polymer dissolved in C₆F₆, itis calculated that the PVE molar percentage in the polymer is 23%.

The IR analysis shows that, in the polymer spectrum, there areabsorption bands in the carboxyl zone, whose intensity is 10 timeshigher than that obtained from a film of a MOVE 1/TFE copolymer preparedaccording to Example 10 and having the same thickness.

The DSC thermogram does not show any melting endothermic curve,wherefore the polymer is amorphous. The TGA shows a weight loss of 2% at427° C. and of 10% at 463° C. The Tg, determined by DSC, is +15° C.

The polymer intrinsic viscosity, measured at 300C in Fluorinert® FC-75,is 51 ml/g.

EXAMPLE 2 (COMPARATIVE) Copolymer between B-PDE (CF₃OCF₂OF₂ CF═CF₂)/TFE

In a polymerization reactor identical to that described in Example 10,250 μl of perfluoropropionylperoxide at 3% by weight in CFCl₂—CF₂Cl, 10mmoles of β-PDE, and 18 mmoles of tetrafluoroethylene, are in sequenceintroduced.

The procedure described in the previous Example 10 is followed until thethermostating step at the temperature of 30° C. under magnetic stirring.

By the ¹⁹F-NMR analysis carried out on the polymer purified of monomersby the processes described in the previous Examples, it is calculatedthat the molar percentage of β-PDE in the polymer is 23%.

The DSC thermogram does not show any melting endothermic curve whereforethe polymer is amorphous. The T_(g), determined by DSC, is −4.8° C.

This Tg value is clearly higher than those obtainable with the vinylethers of the invention (see the above Examples).

EXAMPLE 3 (COMPARATIVE) Crystalline copolymer PVE/TFE (PFA)

One operates as in Example 9 except that in this case theperfluoropropylvinyl ether (PVE) is used instead of α-PDE to obtain acopolymer having MFI equal to that of the Example copolymer of 9.

The IR analysis shows absorption bands in the carboxyl zone, theintensity is of which double those obtained for a TFE/MOVE 1 copolymerfilm of equal thickness and prepared according to Example 9.

1-26. (canceled)
 27. A polymer obtained by the polymerization, alone orin combination with one or more copolymerizable comonomers, of afluorovinyl ether of formula:CFX═CXOCF₂OCF₂CF₂OCF₃ wherein X is F or H.
 28. The polymer of claim 27wherein the fluorovinyl ether is copolymerized with one more comonomersthat is a fluorinated compound having at least one polymerizablecarbon-carbon double bond.
 29. The polymer of claim 28 wherein thefluorinated compound further comprises at least one atom selected fromthe group consisting of hydrogen, chlorine, bromine, iodine, and oxygen.30. The polymer of claim 27 wherein the fluorovinyl ether iscopolymerized with one or more comonomers that is a C₂-C₈ olefinicallyunsaturated hydrocarbon.
 31. The polymer of claim 27 wherein thefluorovinyl ether is copolymerized with one or more comonomers selectedfrom the group consisting of: (a) a C₂-C₈ perfluoroolefin; (b) a C₂-C₈fluoroolefin; (c) a C₂-C₈ chlorofluoroolefin, a C₂-C₈ bromoclhoroolefin,and a C₂-C₈ iodofluoroolefin; (d) a fluoroalkyl vinyl ether, having thestructure CF₂═CFOR² _(f), wherein R² _(f) is a C₁-C₆ perfluoroalkylgroup in which 0 or 1 of the fluorine atoms are replaced with an atomselected from bromine and chlorine; (e) a perfluorooxyalkylvinyl etherof structure CF₂═CFOX^(a) wherein X^(a) is selected from a C₁-C₁₂ alkylgroup, a C₁-C₁₂ oxyalkyl group, and a C₁-C₁₂ fluorooxyalkyl group havingat least one ether oxygen; and (f) a sulphonic monomer having thestructure CF₂═CFOX^(b)SO₂F, wherein X^(b) can be CF₂CF₂, CF₂CF₂CF₂, orCF₂CF(CF₂X^(c)), and wherein X^(c) is selected from F, Cl, Br.
 32. Thepolymer of claim 31 wherein the fluorovinyl ether is copolymerized witha perfluoroolefin selected from the group consisting of atetrafluoroethylene (TFE), a hexafluoropropene (HFP), and ahexafluoroisobutene.
 33. The polymer of claim 31 wherein the fluorovinylether is copolymerized with a fluoroolefin selected from the groupconsisting of a vinyl fluoride (VF), a vinylidene fluoride (VDF), atrifluoroethylene, a chlorotrifluoroethylene (CTFE), abromotrifluoroethylene, and a fluoroolefin of structure CH₂═CH—R² _(f),wherein R² _(f) is a C₁-C₆ perfluoroalkyl group.
 34. The polymer ofclaim 31 wherein the fluorovinyl ether is copolymerized with afluoroalkyl vinyl ether having the structure CF₂═CFOR² _(f) wherein R²_(f) is selected from the group consisting of a trifluoromethyl group, abromotrifluoromethyl group, and a heptafluoropropyl group.
 35. Thepolymer of claim 31 wherein the fluorovinyl ether is copolymerized witha fluoroalkyl vinyl ether, having the structure CF₂═CFOR² _(f) whereinR² _(f) is a C₁-C₆ perfluoroalkyl group that is aperfluoro-2-propoxypropyl group.
 36. The polymer of claim 27 wherein theamount of the fluorovinyl ether polymerized is between about 0.1 mole %and about 20 mole %, the remainder comprising the one or morecopolymerizable comonomers.
 37. The polymer of claim 36 wherein theamount of the fluorovinyl ether polymerized is between about 15 mole %and about 20 mole %, the remainder comprising the one or morecopolymerizable comonomers.
 38. The polymer of claim 27 wherein thepolymer is elastomeric.
 39. The polymer of claim 27 wherein the polymeris plastomeric.
 40. A fluoroelastomer according to claim 27, comprisingunits derived from fluorovinyl ethers of formula CF₂═CFOCF₂OCF₂CF₂OCF₃.41. The fluoroelastomer of claim 40 further comprising in the polymerchain, units derived from either: 1) a vinylidene fluoride and at leastone additional copolymerizable comonomer selected from a C₂-C₈perfluoroolefin;,a C₂-C₈ chlorofluoroolefin; a C₂-C₈ bromofluoroolefin;a C₂-C₈ iodofluoroolefin; a fluoroalkyl vinyl ether of structureCF₂═CFOR^(t) _(f), wherein R^(t) _(f) is a C₁-C₆ alkyl group in whichfrom one up to all hydrogen atoms are replaced with fluorine atoms; aperfluorooxyalkyl vinyl ether of structure CF₂═CFOX^(t), wherein x^(t)is a C₁-C₁₂ perfluorooxyalkyl group having one or more ether oxygens;and a C₂-C₈ olefin; or 2) a tetrafluoroethylene and at least oneadditional copolymerizable comonomer selected from a fluoroalkyl vinylether of structure CF₂═CFOR^(t) _(f), wherein R^(t) _(f) is as abovedefined; a perfluorooxyalkyl vinyl ether of structure CF₂═CFOX^(t),wherein x^(t) is as above defined; a C₂-C₈ fluoroolefin; achlorofluoroolefin; a bromofluoroolefin; a iodofluoroolefin; and a C₂-C₈olefin.